No black-and-white method for predator-prey relationships

If it’s bright, don’t bite! Coloration is one of the most common tactics predators use to avoid harmful prey.

Jennifer Hunter, a UC Davis wildlife researcher, conducted a study in which she used skunks to determine whether they were seen as dangerous primarily because of the color of their coats.

The study’s primary interest was to determine how predators distinguished a skunk from other small forest mammals. It examined factors including the black-and-white coloration of the coat and body shape distinct to skunks.

“My study is the first one to my knowledge to study the effects of warning coloration in natural predator prey dyads, in a natural setting,” Hunter said in an e-mail interview.

The procedure involved coloring models of skunks and placing them in 10 sites across California. The models had bait and video cameras secured to them to lure and record predators’ attempts.

Findings emphasized group living and the idea of kin selection – if a member of a skunk group loses its life, then the other members use that as a warning signal, limiting kin casualties.

Hunter’s study also shows that predators use more than warning coloration to detect prey. Skunk predators have learned to avoid their color and shape. When predators spotted the model skunks, they recognized the threatening shape and veered in a different direction.

“Black and white coloring has been seen as a type of warning aposematic coloration, and it is certainly the case with skunks that predators have an innate avoidance because of the coloring that is supposed to yield a negative connotation in their mind,” said Andy Sih, professor of environmental science and policy at UC Davis. “However, as we see with dogs … most animals can’t make the distinction based solely on color. This is where Hunter’s study shows that many factors play into prey-avoidance.”

Hunter’s study demonstrated that species succeed more effectively when more of them are present.

“My study shows when animals live at high density and possess shared warning signals there are survivorship benefits for all, regardless of the relationship between individuals,” Hunter said. “In a nutshell, my study shows that gregariousness is a beneficial strategy at large spatial scales than had been previously thought.”